Analog-to-digital translator



June 28, 1960 G. D. HULST 2,943,311

ANALoG-ToDIGITAL 'rRANsLAToR Filed Jan. '7. 1957 RAT/0 las la Y is? ILL'29 Inventor 6501966' HJ A ltorne y United States Patent@ 2 Claims. (Cl.340-347) This invention relates -generally to analogftordigitaltranslation devices and in particular to .a.dev1ceyfor translatingthevalue of angular shaft positions into coded Y electrical pulses.

Inanalog-to-digital translation devices,`\it becomes necessary tochannel the energy pulses fromthe shaft yread-out elements tosome meanswhich is eapablelof translating these pulses into` the language of themachine forcomputation `or storage purposes. In the priorart,

. such a. translation has been accomplished by means of banks of relaysor switching matrices. The use of banks off relays in the priorartinvolved holding circuits which e were operatedfor switching.advantage `by having `one relaydrop out another relay as the firstrelay was picked.

e There very often is aV chain reaction with thisarrangement or a seriesof relay actions, to wit: pickingholdingand l dropping, for asinglejdata bit change. --It is obviousthat lower Vordered wheel 'is.,arrangedto be. operative in conjunctionwitha control brush for acertain portion such a chain reaction of the relays results invrelatively y slow operation and a requisite sensitive timing.

jIt also has been necessaryin the .translation operation to assure anon-ambiguous read-out from the shaft elements'. ForV instance, inreadingwout thenumbers 39,.V 40

`and 31 and assuming a separate read-out positoin forthe units and tensposition, it is conceivable that flthe brushes did not read exactlytogether, butinstead Vone brushled ythe other,'the translation, mightlread 39, 30, 40 and 41 V0139, 49, 40 and'41. To overcomethis problem,there isbrought into use the lead and the llag brush. `The lead Vand lagbrushes are set'respectivelyefar ahead yandfar behind the normalread-outa point; and by readingfrom ,the lag brush up to a .carry v.timeyancl fromvtheglead' brush' at and beyond the carry time, there isiinsured a non-ambiguous read-out. It is clear that toaccomplish thelead and lag read-out there must be a'controlling device. In certaintranslation devices the controls are accomplished by havingconductive'strtips .ofl80 degrees added to the shafts. commutator strapsand having the read-out pass through jth'ese relays, Ait, is possible to`have either lead or lag readout for one-half the shaft rotation. f* jItalso becomes clear that the above-mentionedv commutator, strap, withjitsinherent mechanical characteristics in combination with the Bycontrolling relays with these relays, gives rise to considerations ofmechanical toler?vv ance and speedlimitations, the-improvement lof whichis desirable for the higher speed operations such as those desired inanalog computers or high-speed control systems.

It is therefore the object of this invention to provide an improvedanalog-to-digital translation device.

It is a further object of this invention to provide a translation devicewhich provides an output `digital change of one or one bit by means oftransferring only one relay.

It is a further object of this invention to provide a translation devicewherein the tolerances for the read-out means associated with the shaftrotating elements is not critical.

In accordance with the above objects the invention time to accomplishthe change. to, addvgan additional singledigit value or dropped out toadd avsingledigitrvalue depending von its energized orrdeenergizedstatus before the addition is sensed. The

.and las madam mntrol 2,943,31 l Patented June 28, 1960 ICC ,features,logical relay-circuitry which provides for adding or subtractingfrom-thetranslation answer one digit value at a Atime While onlyrequiring one relay operation at a A relay may be picked inventionfurther features coded Wheels attached to the -shaftwwhich serves as aYprimary source of shaft position information. lAnadditional featureofthe invention is -the provision of leadand lag readout means to insurea nonfambiguous readout. YIn conjunction with the coded -,wheels and theleadand lag readout the `invention further l,features :that-theV codeinscription itself serves as a control forthe lead Aandlag readout.VConductive material on a of .the lower ordered -Wheels rotation toeffect a lead As higher ordered wheels are added to Ytheydevicehthelower orderedwheels act in this control; capacity` aswell as a` sourceof shaft angular -positioninformatiom 4 The aboveY mentioned and otherfeatures and objects of Athis invention'will beeomemovre apparent byreference to thefollowing descriptiontaken in conjunction with the accompanyingdrawing inrwh-ich the figure isa combination schematic `andcircuit representation of an analog-to! digital `translation device.

in ,thepiigurethereareeshown'two code wheels 11 and 1,2. Oncode wheel 11there is aset of read-out brushes -13. On code wheel '12 therekis a vsetof lead read-out "brushesg14, and a setv'of lag read-out brushes 15. Theindex relay icoil 16Vis vconnected to the read-out brush 17. VThemovable contacts 18- are connected mechanically vvith andactuated by therelayr coil 16. The relay coils 19' through 27 are connected through themovable contactsgllalnd points 28 to they lead and lagreadout bru shes14and 15. "Ihe relay points 29 are coupled to the read-out voltage source30 and to the output means 31,shownxas 'light' bulbs -in the figurereading in binary number notation. Amore comprehensive understanding 1`of the invention `will result from the following discussion taken in,coniunction with the figure.

' The .tigure showsfthedevicereadingSll. On wheel 11 only;brush-17is-resting on conductive material. A circuit Vfrom the read-insupplyy32, to junction 33, to conductive strip 34, throughf.brushu 17, throughcoil 16, to

,the Vother sideof .the supply 32 causes coil 16 to be energized.Withcoil16 energized,y the movable contacts ,-18 .are attractedto ,reston the normally open points of 28. Onl wheel 12 theonlyread-out brushonythe conductive material isbrush 35. A circuit from the read-in supply32,through junction 33, to :segment 36, through ...brush 35, throughEnormally.open, point 37, through coil mi.Y

` ,co il.,27 and thustransfer the movable contacts 38 and 39. withmovablecontacts 38 and 39 transferred, all the bulbs VUareilluminatedLwhiichresultsin a device reading addi- 27, to` lthe otherside of thesupplyZ serves to energize tively, in binary numbers, thevalue 511. As the wheels 11 and 12 rotate clockwise, the brush 17 movesoff the segment 34, and the relay coil 16 becomes deenergized droppingout the movable contacts 18. The transfer of the movable contacts 18results `in the deenergizaton of coil 27 which, in turn, causes themovable contacts 38 and 39 to shift to their unenergized position. Withthe transferred. With the straps 42 and 43 resting on the normally openside, the light bulb number l1 is illuminated, giving a correct readingof the Shaft position.

* By following the rotation of Wheel 11 and noting the the number 2 bulbis glowing, relay 19 is -still energized;

and as wheel 11 approaches the value 3, relay 19 is deenergized. Withthe deenergization of relay 19 and the dropping out of the movablecontacts 42 and 43, the bulb 1 is again illuminated, thus having bulbs 1and 2 glowing at the same time to give the correct additive answer of-l|2==3, This circuitry pattern follows, and the next significant stepin the discussion occurs at the time that wheel 11 reaches the value 16.When wheel 11 reaches the value 16, brush 17 makes contact vwith theconductive material at 46 rand thereby causes relay coil 16 to beenergized. v'At' this saine-"time, wheel P12 has moved to a positionwhere brush 47 is making contact with the conductivey segment at 48.Coil 16 having been energized,-the *st-raps -13 are transferred andbrush 47 ureads out through' the' normally open point 49 and the relaycoil 23 is'energized to light up bulb 16. As wheel "11 continues torotate until brush 17 leaves the segment 'at 34, wheel 12 will havemoved into a position where brushes 48,50 and 51 will be on theconductive segment. When brush 17 Yleaves the segment 34- and coil 16 isdethe readout from said lirst wheel between said lead and 1. Atranslation device for translating angular shaft positions into codedelectrical pulses comprising an input shaft, iirst and second c'odewheels, means coupling said code wheels to said shaft for rotationtherewith whereby said first code wheel rotates a smaller amount thansaid second code wheel for the' same amount of shaft rotation, lead andlag readout means coupled with said rSt spending code wheel, and' eachassigned a different order of value, each output relay having a pair ofmovable contacts, each of said movable contacts having an associatednormally open point and normally closed point, connecting meansassociated with each output relay coupling the normally associated openpoint of one of said movable contacts to the normally associated closedpoint of the other of said movable contacts, logical circuitry meanscoupling each of said movable contacts to an associated one of saidconnecting means of the next higher ordered output relay, and circuitrymeans coupling said logical circuitry means between said output meansand both said single and said lead and lag readout means to effect achange of one digit value in said translation output by a singletransfer of said movable contacts.

2. A translation device for translating angular shaft positions intocoded electrical pulses comprising an input shaft, first and second codewheels, means coupling said code wheels to said shaft forrotationtherewith whereby said iirst code wheel rotates a smaller amount thansaid second code wheel for the same amount offshaft rotap tion, lead andlag readout brushes coupled with said rst ,code wheel, single readoutbrushes coupled with said sec'- ond code wheel, a transfer relay with aplurality of normally open points, normally closed points and movablecontacts, said transfer relay points coupled to said leadlag brusheswhereby each pair of lead-lag brushes for any coded bit is coupled tothe normally open and normally closed points associated with aparticular movable contact, a transfer relay control circuit coupled tosaid single set of readout brushes to control the transfer of lagreadout brushes for a particular angular rotation of said second wheel,a pluralityof devices for representing said shaft angular positions incoded form, a plurality of output relays arranged in two groups, eachgroup coupled respectively to a corresponding code wheel, and eachassigned a different order of value, each output relay having a pair ofmovable contacts, each of said movable contacts having an associatednormally open point and Vnormally closed point, connecting meansassociated with each output relay coupling the normally associated openpoint of one of said movable contactsV to the normally associated closedpoint of the other of said movable contacts, logical circuitry meanscoupling each of said movable contacts to an associated one of saidconnecting means of the next higher ordered output relay, and cirdcuitry means coupling said logical circuitry means between Ysaid meansand both said single andIV said lead-lag readout means to elfect achange of one digit value lin said trans- Electronic Equipment, August1955, page 13. Y

